Centrifuge devices and methods of the present nature have been known in the art. These devices and methods are, generally, characterized by their abilities to separate and/or wash very finely divided particulate material suspended in a liquid where that particulate material is to be substantially conserved and/or where that particulate material must be separated or washed in an isolated environment. Devices and methods of this nature, therefore, have their greatest utility in connection with the separating and/or washing of blood and that is also the preferred embodiment herein. Thus, while the invention is of broader applicability as indicated above, the invention will be primarily described in terms of this preferred embodiment for the sake of conciseness.
As is well known, human blood obtained from volunteer donors often contains constituents which should not be transmitted into the blood stream of the blood recipient. While it is possible to identify blood having these unwanted constituents, it is difficult to remove those constituents from the blood and the blood is often rendered useless or can be used only for less critical application, such as the production of plasma and the like.
The art has proposed various devices and methods for washing blood to remove unwanted constituents such as contaminants, toxicants, viruses, medicants, glycerines and the like. Many of these devices and methods center around an operation for separating the blood cells, especially the red blood cells, from the plasma and, after washing the blood cells, resuspending the cells in uncontaminated plasma or other suitable blood cell resuspending liquid. This is particularly useful for blood bank purposes where common viruses, such as hepatitis viruses, are washed from the blood and the washed blood can then be used in the blood bank. In another mode of use, blood containing unwanted medicants, such as barbituates and the like, can be washed and returned to the donor/patient. Similarly, allergens and serum proteins can be washed from blood. Also, the devices and methods can be used to deglycerinate previously frozen but thawed whole blood (frozen blood has glycerin added thereto). Or cellular debris can be removed from whole blood since particles of different densities will form different layers in a centrifuge as is well known. Other similar kinds of separation and/or washing operations can be performed with these known devices and methods.
While a wide variety of devices and methods have been proposed in the art, the most successful devices are based upon a centrifugal separation of the blood cells from the plasma, with subsequent counter-flow washing of the blood cells. For example, whole blood is placed in a centrifuge device, which, when revolving, forces the cells into discrete areas where the blood cells are compacted. Thereafter a washing solution, such as a sterile saline solution, is passed through the compacted blood cells to wash those cells of unwanted constituents, as indicated above.
The general arrangement and operational requirements of such known devices and methods are disclosed in U.S. Pat. No. 3,347,454 issued to the present inventor. However, the devices and methods of that patent require that the components of the device which actually contact blood be either entirely replaced or completely cleansed after each use, since a batch of contaminated blood could pass a portion of those contaminates to a succeeding batch of blood processed in the device, if replacement or cleansing of the device is not performed. Further, the device is of a batch operation character and can process blood only at a relatively low throughput per unit time.
It was recognized that improvements in the ability to wash succeeding batches of blood were desired and U.S. Pat. No. 3,561,672, issued to the present inventor, provides an improvement of that nature. That patent provides disposable receptacles which can receive a plurality of batches of blood for simultaneous washing in a single centrifuge operation. Independent and adjustable pressure heads for each of the plurality of batches within the centrifuge are provided to control the flows of wash liquid through the respective batches of blood. The disposable units include the blood receptacles, associated conduits and seal devices. The operation of this device is described in some detail in CONTINUOUS FLOW CELL WASHING SYSTEM, Schultz and Bellamy, TRANSFUSION, Volume 8, No. 5, September-October, 1968, and a pre-packaged combination of two receptacles, associated seal devices and conduits is described in detail in A Disposable Counterflow System for Washing Erythocytes in a Centrifugal Field, Schlutz and Bellamy, Proc. 12th Congr. Int. Soc. Blood Transff., Moscow 1969 Bibl. Haemat., No. 38, Part II, pp. 350-358 (Karger, Basel, 1971).
Thus, the art has available considerable details of operation, construction and associated equipment for centrifuges of the present nature and those details will not be repeated herein. The entire disclosures of the above noted patents and publication are incorporated herein by reference and relied upon for the aforementioned details.
While this ability to provide a disposable package and sterilized component system for washing blood is the basis of one of the most successful commercial uses of a blood washing apparatus, that arrangement has the disadvantage that only a relatively low number of separate receptacles can be conveniently handled without so severely complicating the disposable unit, the apparatus and the associated equipment as to make the device and method impractical. Indeed, the commercial embodiments thereof contained only two blood receptacles, along with their associated seals and conduits. This results in a relatively low throughput of blood in a time period.